Apparatus for the continuous production of cement-fiber sheets



3 1 7 t 3 w m h S I. t 2 w h s 2 July 7, 1953 P. SALVANESCHI APPARATUSFOR THE CONTINUOUS PRODUCTION OF CEMENT-FIBER SHEETS Filed July 31, 1947lm'enfar 3 3w dam/yaw: iwqflyl? y 7, 1953 f P. SALVANESCHI 2,644,373

APPARATUS FOR THE CONTINUOUS PRODUCTIQN 0F CEMENT-FIBER SHEETS 2Sheets-Sheet? Filed July 31, 1947 I r 5 ,w w m M M w A .5 f u A 6 0 N mm3 I. o o P .m mm mm on n 3 E m 8 v mu mm on 4 h mm mm o N pm 0 H an Aprocess is already known tio n of pipes and'other similar hollow bodiesin which tubes are formed on a porous or permeable cylinder, inside'ofwhich a vacuum is'applied, through the action of one ormore vibratoryfeedtetbleSi-bonveniently operated around said cyl- Patented July 7,1953 1 UNITED STATES PAT NT; OFFICE APPARATUS FOR THE CONTINUOUS PRO-DUCTION 0F CEMENT-FIBER SHEETS Pino Salvaneschi, Bron i, Italy 4Application July-31, 1947, Serial No. 765,092 In Italy October 31, 1942Section 1, Public Law 90, August s, 1946. i"

Patent expires October 31, 1962 '1 Claims.

-The present inventionrelates to a process and apparatus for producingsheets composed of mixtures offibers and cement. Y I

for the producinder.

-Intheabove mentioned known process, the production of the pipe throughthe formation of a layer "of'the desired thickness on the cylinder 1after the latter has accomplished only one revolu- "tionis'obtained.'-'1 1 Furthermore, this known process provides a v vibrocompactingaction;exertedsimultaneously with the revolving 'motion and theapplication of vacuum in the inside ofcylinder. a w r -To produce cementsheets, for'example,-from mixtures offibers and cement or the like, itis expedient to form, by the above specified process, a ;pipe ofsuitable length and diameter, which is "theiicut along a generatrix, andfinally unwound on a plane; {This system of cutting'and unwinding i'S-already known, and generally applied-in j'p'asteboa-rdmaking by wellknown machines.

However; itisobvious that the above mentioned known proce'ss onlypermits intermittent or discontinuous production. Moreover, the amountof additional processing off-'the sheet produced in such a-manner'depends,- at least to'a certain extent, uponits length, andconsequentlyupon the-cylinder diameter. 'It follows that,- after all,

-'should sheets of various length be produced,

either the-"cylinder has to be replaced to have a circumferencesubstantially equal to the length ofthe desired sheet, or large lossesofmaterial inthe' form' of 'scraps have to be suffered as the -length-ofthe formed sheet is trimmed to the desired dimension.

All of'the "above specified disadvantages'can be prevented by combiningthe known process with asystem which applies the vacuum in timedrela'tionship to the action of feeding and vibro- {compacting device'sassociated with. the rotated cylinder in accordance with the presentinven- Accordingly, an object of the present inven- :tion is toprovide aprocess which allows continu- I -.-ous production of sheets-of constantwidth and indefin e, c st of s cce s vin Q constant. w dthr n a e te m nl t is al a oss bl i t Process e bqfiy i th iiqe.ta-gbtaiasheets=rtfaelreesirl1inis hed sides, by giying to thesurface on 'which the sheets are formed a shape such as to sharplydelimit the edges of said sheets, and/or to give to the sheets apredeterminedprofile.

Moreover, the devices-for the carryinginto effect of this invention areof simpler design,

being also more economically joperated'than' the already known types,"and adapted to produce roughened, striped or longitudinally ribbedsheets, which are therefore particularly suitable'for'linings,coatings-or the like. I

It has been ascertained thatfshort fibres inay be advantageously;employed for obtaining-a product-with high waterproof properties andstrength, by reason of the peculiar distribution of the fibers causedbythe action of the'vibrat- 'ng feeding hopper and of thevibro-compacting devices.

' In the accompanying drawings, illustrative embodiments of theinvention are shown, by way of example, but it is to be understood thatit is possible to carry into effect the'invention through other types ofapparatus without departing from the'scope of'the invention. Inthedrawings:

"Fig. "'1 shows a diagrammatic cross-section of a machine for thecontinuous production of fsheetsn Fig, 2 shows an endless travellingband, fitted the machine of the-kind shownin Fig. 1, for

the continuousproduction of successive sheetsof predetermined length;Fig. 3 shows another machine for the continuous production of sheetshaving a predetermined length. r p

Fig. 4 shows a detail of the vibrating hopper of the device in Fig. 3.

Fig. 5 shows a detail of the vibrating compacting or compressing unitassociated with the device'of Fig.3. 7

Fig. 6 shows a vacuum slide-valve, to be employed with the apparatus ofFigs. 3 to 5, inclusive. L

" Referring first to Fig. 1,-wherein an apparatus embodying the presentinvention 'is illustrated,

reference numeral {I indicates a rotatable hollow drum or cylinderhaving a porous or permeable peripheral wall and mounted for rotationabout a horizontal axis. The opposite ends of the'lc'ylinder l arepreferably sealed by end'walls, and

a unit is provided in the interior of the'drum for exerting aninwardly-directed suction effect on successive portions of the porousperiphery of, the. cylinder, as the latter is rotated. This suctionexerting unit includes angularly related radialflwallsi andi l'h eldfixed position withtion 9. V sothat the-section 8 moves relative theretoas frontwall. I0. the lower; portion of the front wall I acts" to 3 inthe cylinder and extending from the axis of rotation of the latter,substantially to the inside surface of the cylinders porous periphery.Sealing elements 3 and are carried by the outer edges of the walls 2 and4, respectively, and engage slidably against the inner surface of thecylinders periphery. A conduit connects to the space defined betweenwalls 2 and 4, adjacent the junction of the latter, and leads to anevacuating device (not shown) of conventional construction for exertinga suction or vacuum against the inside of the portion of the cylindersperiphery located between the sealing elements 3 and 5. As the cylinderl rotates and the walls 2 and 4 are stationary, it is apparent thatprogressive sections of the cylinders periphery are successivelysubjected'to theisuction or vacuum in the space between walls 2 and 4.

As seen in Fig. 1, the walls 2 and 4 are anguv larly related byapproximately 60, with the wall ,z'extending substantially verticallyupward from the axis-of rotation and with the wall 4 being inclined inthe direction of rotation of the cylinder as indicated by the arrow.Thus, as the cyltinder I .is rotated, the peripherythereof is exposed toVacuum as it passes the uppermost position and continues tobe so exposedfor approximately the following 6090f rotation. The interiorof cylinderI,'not included in the space between walls 12 ;and 4, is communicatedwith the atmosphere, so that, as the periphery of the cyl- =indermovespast sealing element 5, the pressures-inside and outside of the porousperiphery are equalized and continue thus until the sealing element 3"isagain reached. d q

A'fabric or porous felt'band. l2 extends: over v at least that portionof the periphery of cylinder l which is defined between the sealingelements 3 and 5 and moves with the cylinders periphery asthe latter isrotated. Upon leaving the periphery at a point after sealing element 5,the .band orweb I2 is supported by a suitable conveyor I1 for example, aroller conveyor of conventional construction. The band or Web [2 has awidth slightly in excess of the width of the.

sheets to be formed thereon. I d

The mixture of fiber and cement, or other similar materials, from whichthe sheets are to be formed, is preferably in a pasty or damp con-..dition, as distinguished from the wet mix or .10; which, at its lowerportion, extends parallel to the'periphery of cylinder I and a" rearwall formed by an upper section 8 and a lower sec- The lower section 9may be stationary,

the hopper is vibrated, or for "the sake of simplicity may be secured tosection-,8 for movement with'the latter.- Side walls complete the hopperand may move with the front and back walls or be stationary. At leastthe front wall l0 and the rear wall section 8 are secured togetherandare mounted for vibrating motion in the direction of the two-headedarrow of Fig. 1 and about an axis H displaced forwardly of the Thus, asthe hopper is vibrated,

compress or' compact the pasty ordampmixture distributed on the surfaceof web or band I 2. Since the underlying portion of the cylindersperiphery and hence the porous web l2 are subjected to a vacuum duringthe distribution and initial compacting of the mixture, water and airare withdrawn from the mixture into the space between walls 2 and 4 andthen evacuated from that interior space by the vacuum producing deviceassociated therewith. Further, the'vacuum or suction acting on the undersurface of'band l2 during distribution of the mixture on the latterserves to ensure the even distribution of the mixture over the entiresurface of the band subjected to the vacuum.

Arranged in front of the hopper I, that is, spaced from the hopper inthe direction of the rotation of cylinder 1, is a compacting orcompressing device which includes a hammer or com- .pa'cting'f member I3 mounted on an arm [4 pivotally mounted at l5 for vibratory movement inthe direction of the two-headed arrow so'that the member l3 subjects thesheet [6 being produced to repeated and rapid compacting blows duringthe terminal portion of the travelof the band I 2 over the space definedbetween the seals 3 and 5. Thus, the remainder of the moisture and airoccluded-within the mixture is driven out of the sheet I 6- andevacuated while the sheet is simultaneously compacted to increase thedensity and strength'thereof.

When the band [2 has-moved past the sealing element 5, and is no longersubjected to the vacuum effect, it is free to be. removed from theperipheral surface of cylinder. land to be guided by the rollerconveyors I! with the plastic continuous sheetlfi thereon. In-the deviceof-Fig. l, the band or web -I2;is of substantially great length and isintendedto be wound. on and off two drums (not shown) located atopposite sides of the illustrated device as motion is imparted to theweb or band by the rotated cylinder 1.

In the embodiment of the invention illustrated in Fig. 2, partscorresponding to thosedescribed in conncetion with the device of Fig. 1arev indicated by the same reference numerals. The

embodiment of Fig. 2 is-intended to continuously producesuccessivesheets0f predetermined length rather than the onecontinuous sheet ofindeterminate length produced with the previously described device. Inorder to continuously produce such successive sheets, the web of bandIZ-of the device-in Fig. 2 is provided with solid or impervious ribs l8rigidly fixedon-the bandand extending transversely on the latter. Theribs are slightly shorter than the width of the band,iand slightlythinner than the sheet to be produced. The band 12 is a continuouselement and passes over a loose or idler roller 19. 20 is a revolvingbrush with water sprayer, and diagrammatically represents a band washingdevice in place of which one of the already known beater types, havinga'beating action integrated with the water sprayer, mightbeemployed. Thewalls 8- and- [0 of the hopper I, together with the vibrated compactingmember l3,rbehave precisely as shaking tables, as in the embodiment ofFig. 1, and are suitably located and operated adjacent the cylindersurface. In the apparatus of Fig. 1 or 2 the mixture, whichis-continuously poured into the hopper! by the pipe 6, is uniformly andregularly fed onth'e band owing to the'combined effectof the-gravity, ofvibrations, of the suction and of the forward motion of the band whichisdriven'by the -revolvin'gporous or 'permeablecylinder.

gof the band I2.

The numeral 2| is the A portion of the excess water, and the most of theair contained in the mixture, after filtering through the fabric bandl2, fiow through the porous peripheral wall of the cylinder, then aresucked into the space defined by the walls 2, 4 and sealing elements 3,5 and exhausted by the associated vacuum pump. The wall ll) of thevibrating hopper acts, as already said, as a shak- '.ing table, byfeeding the mixture and causing a taneously with the relative motion ofthe sheet carried by the band, and with the suction effect exertedinside of the length of cylinder defined between the seals 3 and 5. a

, In each of Figs. 1 and 2, only asingle hopper is shown by way ofexample. In the practice,

' however, it maybe necessary to employ several hoppers, actingsuccessively, in order to produce a sheet composed by a number ofsuperposed layers, of the same or different fibrous or nonfibrousmaterial. The same can be said for the vibratory compacting device, ofwhich more than one may be employed, with the purpose of repeating thecompacting of the sheet, as well as smoothing and finishing the-latter.

After the continuous sheet has been produced on the device'of Fig. 1,the, sheet is cut transversely as desired by means of one of the alreadyknown devices, such as automatic shears, a thin Carborundum wheel, or asuitably arranged bandsaw. The sheets so obtained can'be submitted tofurther processing. Another band can be secured to the trailing end ofband l2 so as to obtain a continuous production. The band'l2,

conveniently wound-up on a drum, can be employed again after having beenwashed.

The variation shown in Fig. '2, permits the elimination of all handwashing and manipulations of the band, since the band in this embodimentis of the endless type. Moreover, this arrangement is adapted for thecontinuous production of sheets already cut to the desired l8 fixed onthe band and made length. The ribs are slightly shorter of metal, rubberor leather,

than the width of the band, and slightly thinner than the sheet, andbeing impermeable eliminate the suction effect in the areas, of the bandcoveredby the ribs so thatthe mixture discharged -onto the ribs is drawnoff the latter onto the adjacent exposed areas of the band, no mixtureremaining on the ribs, and consequently sheets can'be obtained which arealready'cut and finished on all four sides. The numeral I! in Fig.

4 2 is one of these finished sheets, and to takeoff .the same, it issufficient to lay on it a plate; with a curvature equal to that whichshall be taken .by the plastic sheet when, being no longer rel tained bythe suction effect, it will only besubjected to the gravity action andwill-fall clear The variation of Fig. 3, together with the correspondingdetails (Figs. 4, 5y'and 6), shows apparatus for carrying the inventioninto effect, by which the practical requirements can be better fulfilledwhen cylinders of large diameter are employed. g a

frame, on which the cyl- 6 inder 40, the axles 26 andil4, and theshafts130 and '38 are fitted. The cylinder 40 is supported thereof intoan annular groove formed in a face of the member 52. The periphery Ofcylinder 40 is in the form of a hollow annular channel of. substantiallyrectangular cross-section (Fig. 4) and having spaced radial partitionstherein (Fig. 3) .to divide the interior of that channel .into aplurality of relatively sealed chambers: a,

11., each having a porous or foraminous outer wall. Each of the cylinderchambers is connected to a radial pipe communicating the respectivechamber with the radially opening end of the related port or passage ofvalve member 52.

e An annular distributor member 45, fixedly mounted in relation to theframe 21, engages slidably in the groove formedin the face of valvemember 52 (Fig. 6) and is:formed with a hollowed out section 4Bextending circumferentially for approximately 90 and opening axially atthe side of the distributor engaging in the valve member groove forcommunication with the axially opening ends of 'the successive valveports as the latter come into registry with the hollowed out section 46.A conduit 41 connects. to the hollowed out section 46 and communicatesthe latter with a vacuum pump (not shown) or other similar device forestablishing a vacuum or relatively low pressure in the hollowed-outsection of distributor 45, and hence in those chambers of thecylinder'periphery corresponding to the valve ports registering with thesection 46. As shown by the dotted lines in Fig; 3, the hollowed-outsection 46 is disposed'tooccupy the upper left quadrant of thecircular'path of the valve member 52, so that, with the cylinder in theposition of Fig. 3, chambers Z, m, n and a are'subjected to the vacuumeffect. As the cylinder 40 is rotated, in' the direction of the arrow ofFig. 3, the chambers successively occupying the positions of thechambers Z, m, nand a in that view'are subjected to the vacuum effect.Seals 49 and 50 are carried by the distributor 45 and engage againstvalve member 52 to prevent leakage at the sliding surfaces oftheseelements. As seen in Fig. 6, the distributor 45 is also formed.with an annular slot 48 extending therethat, as a chamber moves past thepositionof chamber I in'Fig. 3, such chamber is vented to the atmosphereto equalize the pressures atuthe opposite sides of the porous outer wallthereof.

A webor band of porousmaterial may run over the cylinder '40, as in thepreviously, described embodiments,or the sheets may be formed,

directly on the surface of the cylinder which is provided withcircumferentially spaced transverse ribs 379 of impervious material, sothat, as in the apparatus of Fig. 2, successive sheetsof predeterminedlength are produced by. reason of the fact that the vacuum is onlyeffective at opintermediate areas between successive ribs.

The pasty or damp mixture is conveyed to the location of the machine bya duct 6 which discharges into a hopper 22 similar to the previouslydescribed hopper l. Hopper 22 includes a front wall having a lowerportion formed to com- .pact the mixture against the cylinder surface asthe hopper is vibrated, a rear wall including an upper section 23vibrating with the front wall ..and a lower section 24 which may beformedof resilient material, such as rubber, to permit the .ribs 39 topass under the hopper to finish the side edges of the sheets during thefinal compacting of the latter.

In operation, the apparatus Of Fig. '3 performs substantially in thesame manner as the devices described in connection with Figs. 1 and 2.When a section of the cylinder arrives under the hopper 22 and issubjected to the vacuum effect, the pasty mixture is discharged onto thecylinder in -the form of a sheet and is initially compacted by thevibrated front wall 25 of the hopper s0 that the removed water and airare drawn inwardly through the porous cylinder periphery into theunderlying cylinder chamber for evacuation by the vacuum pump.

When, owing to the revolving motion of the cylinder, a sheet is broughtout from under the compacting element 32 and the pressures at oppositesides of the cylinder wall are equalized, the

sheet is removed in the manner previously described, while on theopposite side of the cylindivide the cylinder in whatever number ofchambers may be desired for producing any desired number of sheets ateach revolution Of the cylinder.

Moreover, the apparatus shown in Fig. 3 can be provided with the endlessband or web of Fig.

2, with or without the ribs 18, or with an elongated web combined withor without the roller table ll of Fig. l.

It should be noted that with the apparatus and process heretoforedescribed, the thickness of the sheet can be varied from point to pointof its cross-section by suitable shaping of the =hoppers, cylindersurfaces and compacting elements. Therefore, it is possible to producelongitudinally striped 0r ribbed sheets, since this exclusively dependsfrom the profile of the hopper- -wall 25, andof the vibratorycounter-mold or compacting elements 3| and 32.

As in the embodiments of Figs. 1 and 2, the apparatus Of Fig. 3 mayinclude more than one hopper so that sheets may be produced; which arecomposed of successivelayers of the same or different mixtures.

Having now. particularlydescribed and ascertained the nature of my saidinvention and in what manner the same isto be performed, I declare thatwhat I claim is:

1. A device for making cement-asbestos sheet material comprising arevolving drum rotating about a horizontal axis and having a permeablecylindrical wall, a permeable belt travelling eralwall. 55

a filtering web running over said peripheral wall aroundsaid drumfor anangle of less than 360,

means for creating a vacuum at the insideof part of the portion of saidcylindrical wall covered by said'belt, a hopper for discharging a pastycement-asbestos mixture downwardly onto the initial portion of said partof the beltand including a surface lying against said initialportion ofsaid part of thebelt on said drum, a second surface lying on said beltin succession after said first mentioned surface, means for oscillatingsaid first mentioned and said second mentioned surfaces indirections-angularly disposed -to said respective surfaces, and meansfor removing the material formed on said beltafter the belt has left thedrum. I

2. Apparatus for the continuous production of cement-fiber sheetscomprising arotatable'cylinder mounted for rotation about a horizontalaxis and having a porous peripheral wall, a hopper disposed fordischarging a pasty cementfiber mixture downwardly onto said wall of thecylinder and including a hopper Wall section extending along andadjacent to a portion of said peripheral wall of the cylinder, means forvibrating said hopper wall section in the direction radially of saidcylinder, means for creating a vacuum at theinside Of said peripheralwalland over a zone extending from the location of said hopper in thedirection of rotation for less than 360, compacting" means disposedadjacent said peripheral wall at the terminal portion ofsaid vacuum zoneand including a rockable member I mounted at its center for-swingingabout an axis parallel to said axis of the cylinder, compacting'elements at the opposite ends of said rockable tive tosaid rockablemember in the direction ments may be equalized.

- 4. Apparatus according to claim 2; wherein said compacting elementsare formed with pro- 'jections at the opposite ends thereof forfinishing the side edges of the mixture on said periph- 5. Apparatusaccording to claim 2; including and in contact with the latter at leastthroughout said vacuum zone.

6. Apparatus for the continuous production of cement-fiber sheetscomprising a cylinder rotatable about a horizontal axis and having aporous peripheral. wall, a hopper disposed for dischargthe vacuum at theareas of said peripheral wall disposed between successive imperviousribs, means for. compacting the mixture on said pe- '9' ripheral wallduring passage through said vacuum zone, and means for removing thecompacted mixture from said peripheral wall after passage out of saidzone.

7. Apparatus according to claim 6; including an elongated filtering Webcarrying said ribs and contacting said peripheral wall at leastthroughout said zone for receiving the discharged mixture.

PINO SALVANESCHI.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 775,511 Binns Nov. 22, 1904 I 1,347,724 Wagner July 27, 19201,547,613 Salisbury July 28,1925

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